This study investigates how Software Defined Networking (SDN) paradigm can be used to ensure high-quality uninterrupted Voice over Internet Protocol (VoIP) service accompanied by video for prioritized users in a network congested with background traffic. Guaranteeing a level of Quality of Service (QoS) and resource prioritization are vital in an emergency situation such as an international disaster recovery operation. Providing QoS in such scenarios with the help of SDN is very feasible, via limiting bandwidth, assigning flows to different switch queues and/or adapting routing decisions depending on network conditions. Here we compared loss rate and latency as QoS metrics under several scenarios and results showed that we can flexibly manage the QoS by reducing more than 5% of loss rate and more than 50% of latency.